A bimetal switch wherein a bimetal member and a PTC member are closed to each other and integrally combined is known as a component which opens between contacts being closed in an electrical circuit. In this component, the bimetal member and the PTC member are connected in parallel. Such a bimetal switch is constructed so as to open between contacts by actuating the bimetal member when a temperature of its surrounding environment is abnormally high, while at the same time, a current which flows via the bimetal member is diverted so as to flow via the PTC member.
For example, when a current flowing through a circuit becomes excessively large so that a temperature of an element constructing the circuit becomes abnormally high, such high temperature raises a surrounding temperature of a bimetal switch, thereby the bimetal member acts to open contacts. Even when the contacts are opened as mentioned above, a high potential difference no longer immediately occurs because the current is diverted, and a fusion between the contacts can be prevented as much as possible. The bimetal member of such a bimetal switch is actuated by a high temperature around the bimetal switch as mentioned above.
International Patent Publication WO 2008/114650 is a prior patent reference.